Integrated circuits incorporate complex electrical components formed in semiconductor material into a single circuit. Generally, an integrated circuit comprises a substrate upon which a variety of circuit components are formed and connected to form a circuit. Integrated circuits are made of semiconductor material. Semiconductor material is material that has a resistance that lies between that of a conductor and an insulator. The resistance of semiconductor material can vary by many orders-of-magnitude depending on the concentration of impurities or dopants. Semiconductor material is used to make electrical devices that exploit its resistive properties.
It is desired to design integrated circuits in which electrical components and circuits within the integrated circuit do not interfere with each other. One method of accomplishing this is by including differential circuits. A differential circuit is a circuit that is really two circuits with opposite voltages and currents. That is, a differential circuit comprises a first circuit that produces desired voltages and currents and a second circuit that is identical to the first circuit that produces opposite voltages and currents. The opposite voltages and currents work to cancel out parasitics that naturally occur because of the voltages and currents and helps isolate the circuit from other circuits in the integrated circuit. Further discussion on parasitics can be found in U.S. Pat. No. 5,717,243, which is incorporated herein by reference.
Symmetric inducting devices are useful in differential circuits. Moreover, it is desired in the art to have a symmetric inducting device that has less resistive loss without introducing other parasitics.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an integrated circuit with a symmetric inductor that has reduced resistive loss with low parasitic characteristics.